This project is a result of program development in relation to and in support of a projected radiation therapy facility a Wayne State University and in the Detroit Medical Center. The present Cancer Center Support Grant was awarded in order to develop program toward the realization of the actual facility. Original objectives were to initiate a radiobiological research program and to develop other programmatic support. Our goals, therefore, for Year -01 have been to develop program, recruit staff and initiate research studies. The three studies which have been initiated since June 1974 are as follows: 1. Response of the Hypophyseal-Adrenocortical Axis to Whole Body X-radiation. 2. Effects of Radiation on the Primary Immune Response in Fish. 3. Serum Cyclic Nucleotide Levels in Tumor Patients as a Function of Radiotherapy. These studies will be continued and considerably expanded in year - 02. The principal significance of these approaches is to amplify current basic knowledge in these physiological areas and particularly as it related to radiotherapy. Our direction for year -02 will be to increase our professional radiobiology staff, to amplify the above-described projects as well as initiating other studies relating to immune mechanisms, to explore radioimmunoassay techniques as applied to problems of clinical radiation therapy, and to further assess reaction to whole body radiation.